WO2022215584A1

WO2022215584A1 - Particulate raw material granulation method and sintered ore production method

Info

Publication number: WO2022215584A1
Application number: PCT/JP2022/015129
Authority: WO
Inventors: 典子小澤
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2021-04-08
Filing date: 2022-03-28
Publication date: 2022-10-13

Abstract

According to the present invention, in a bottom surface of a pan 1 on which a scraper 2 is disposed in a specific state, if a straight line at which a virtual extension surface of a side surface 21 of the scraper 2 intersects the bottom surface and an extension line thereof are defined as a virtual straight line a, and if a straight line passing through the center p of the bottom surface of the pan 1 and parallel to the virtual straight line a is defined as a virtual straight line b, a particulate raw material is poured into the pan 1 such that a particulate raw material-pouring position x is located closer to the center p of the bottom surface of the pan 1 than is the virtual the straight line a, and a center p_x of the particulate raw material-pouring position x is located between the virtual straight line a and the virtual straight line b, and a liquid is poured into the pan 1 such that a center p_y of a liquid-pouring position y passes through the particulate raw material-pouring position x, is located on a virtual straight line c parallel to the virtual straight line a, and falls within a circular region e having a radius of 0.6r, where r is the radius of the pan 1.

Description

Pelletizing method for powder raw material and method for producing sintered ore

The present invention relates to a method for granulating a powdery or granular raw material suitable for granulating a sintering raw material for producing sintered ore and a method for producing sintered ore.

A pan-type pelletizer is widely used as a granulator for powder raw materials. This pan-type pelletizer is installed with a pan tilted at a predetermined angle, and granulates by rolling the raw material powder in the pan that rotates in this tilted state. A liquid (an aqueous solution containing water or a binder) is added to the raw material for the granular material in the bread, and this liquid exerts a liquid bridging force and contributes to adhesion between the granular materials. Granules come into contact with each other as they roll down from the top of the pan, and are pressed together as they are lifted along the side walls of the pan. be done. In general, in this granulation process, smaller powder adheres to a larger nucleus, and granulation proceeds. In a continuous pan-type pelletizer, when the raw material is granulated to a certain size according to the tilt angle and rotation speed of the pan, the granules that tend to be distributed on the surface layer spill out from the rim of the pan. Thus, products (granules) with uniform particle sizes are recovered.

Pan-type pelletizers are widely used for food manufacturing and pretreatment of industrial raw materials. It is used for granulating sintering raw materials with auxiliary powder raw materials etc.). In order to obtain granules with a certain strength and size by using a pan-type pelletizer, it is important that the liquid for exerting the liquid-bridging force spreads evenly over the raw materials in the pan. .

Conventionally, when granulating sintering raw materials for sintered ore production, the sintering raw materials in the pan are watered (sprinkled) with a hose for watering. In order to spread the water evenly over the raw material for sintering, water is added in several places within the range where the hose for watering can be routed. On the other hand, Patent Document 1 describes a method for producing carbon material-containing granulated particles having a two-layer structure in which the periphery of a carbon material core is coated with a mixed powder of iron ore powder and a lime-containing raw material. , it is proposed to selectively water the area where the carbonaceous core appears on the surface and rolls.

Japanese Patent No. 6683155

The method shown in Patent Document 1 can be said to be an effective adding water method when producing carbon material-containing granulated particles having a two-layer structure, but the granulation target is limited. In general granulation of powdery or granular material using a pan-type pelletizer, in order to evenly distribute moisture in the powdery or granular material to obtain high-quality granules having a certain size and strength, it is necessary to It is considered that the position at which water is added is important, and in particular, it is thought that there is an optimal water addition position in relation to the input position of the powdery or granular raw material. do not have.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the prior art as described above, and to perform granulation of powder or granular material using a pan-type pelletizer under optimal conditions for liquid bridging force. Thus, a method for granulating raw materials for powder and granular material and a method for producing sintered ore are provided, which can stably obtain granules having predetermined strength and particle size and having small variations in strength and particle size. It is in.

As a result of repeated studies to solve the above problems, the present inventors have found that in granulation of powdery or granular raw materials using a pan-type pelletizer, the optimum hydration position (liquid It was found that there is a liquid injection position to obtain cross-linking force. The present invention was made based on such findings, and has the following gist.

[1] A pan (1) rotating in an inclined state, scraping off the powdery or granular raw material adhering to the side wall surface and the bottom surface of the pan (1), and scraping off the powdery or granular raw material on the bottom surface of the pan (1) A scraper (2) for regulating the rolling area is provided, and one end (20) of the scraper (2) is positioned on the sidewall surface side of the inclined pan (1), and its longitudinal direction is one end. Using a pan-type pelletizer arranged in a state in which the upper half of the pan is inclined to the rotating side with respect to the radial direction of the pan with the part (20) as the base point, the powder material and the liquid bridge force are applied to the pan (1). A method of granulating a powdery or granular raw material by introducing a liquid for obtaining A straight line intersecting the imaginary extended planes of and its extension line is an imaginary straight line (a), and a straight line passing through the center (p) of the bottom of the pan (1) and parallel to the imaginary straight line (a) is an imaginary straight line (b) In this case, the feeding position (x) of the powdery or granular raw material (however, the bottom area of the pan where the fed powdery or granular raw material falls) is closer to the center (p) of the bottom of the pan (1) than the imaginary straight line (a), In addition, the powdery or granular raw material is put into the pan (1) so that the center (p _x ) of the powdery or granular raw material feeding position (x) is located between the imaginary straight line (a) and the imaginary straight line (b), and the pan ( 1), the center (p _y ) of the liquid input position (y) (however, the bottom area of the pan where the input liquid drops) passes through the granular raw material input position (x), and the imaginary straight line ( The liquid is poured into the pan (1 ) A method for granulating a powdery or granular raw material, which is characterized in that it is put into.

[2] In the granulation method of [1] above, the center (p _y ) of the liquid input position (y) is located below the powder or granular raw material input position (x) on the bottom surface of the inclined pan (1). A method for granulating a powder or granular raw material, characterized by:
[3] In the granulation method of [1] or [2] above, the scraper (2) comprises a plurality of scraper members (2a) arranged at intervals in the vertical direction of the inclined pan (1), The uppermost scraper member (2a) of them is positioned on the side wall surface side of the pan (1) with one end (20a) inclined, and its longitudinal direction is the pan radius with the one end (20a) as the base point. With respect to the direction, the upper half of the pan is arranged in a state of being inclined toward the rotating side, and the side surface (21a) of the uppermost scraper member (2a) (however, the material scraping surface and the A method for granulating a powder or grain raw material, characterized in that a straight line intersecting imaginary extension planes of two sides) and an extension line thereof are defined as imaginary straight lines (a).

[4] In the granulation method according to any one of the above [1] to [3], granulation of a powdery or granular raw material characterized by granulating a sintering raw material for producing sintered ore as the powdery or granular raw material. Method.
[5] A method for producing sintered ore, characterized by granulating a sintering raw material for producing sintered ore by the granulating method of [4] above, and sintering the granules.

According to the present invention, when granulating a powdery or granular raw material using a pan-type pelletizer, it is possible to charge a liquid for obtaining a liquid bridging force at an optimum position in relation to the charging position of the powdery or granular raw material. Thus, it is possible to stably obtain granules having a predetermined strength and particle size and having small variations in strength and particle size.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 schematically shows an example of a pan-type pelletizer to which the method of the present invention is applicable. Fig. 2 is a plan view schematically showing another example of a pan-type pelletizer to which the method of the present invention can be applied, showing the state of arrangement of a pan and a scraper with respect to the pan; Fig. 2 is a plan view schematically showing another example of a pan-type pelletizer to which the method of the present invention can be applied, showing the state of arrangement of a pan and a scraper with respect to the pan; In the granulation process by a pan-type pelletizer, it schematically shows the movement of the powdery or granular raw material in the pan. ) is an explanatory view showing the movement of the intermediate layer of the powder material layer, and FIG. 4C is an explanatory view showing the movement of the surface layer of the powder material layer. FIG. 2 is an explanatory view showing the powdery or granular raw material charging position and the liquid charging position in the method of the present invention on the bottom of the pan of the pan-type pelletizer of FIG. 1 ; FIG. 4 is an explanatory view showing the powdery or grain material charging position and the liquid charging position in the method of the present invention on the bottom of the pan of the pan-type pelletizer of FIG. 3 ; Fig. 7 (a) schematically shows the side of the pan, and Fig. 7 ( A) is an explanatory diagram showing the bottom surface of the pan. Fig. 8 (A) schematically shows the case where the liquid input position in the method of the present invention is higher than the granular raw material input position on the pan bottom surface of the pan-type pelletizer. A) is an explanatory diagram showing the bottom surface of the pan. FIG. 4 is an explanatory view showing an example of the powdery or granular raw material charging position in the method of the present invention and a region where a liquid charging position is provided for the powdery or granular raw material charging position on the pan bottom surface of the pan-type pelletizer. FIG. 4 is an explanatory diagram showing another example of the powdery or granular raw material charging position in the method of the present invention, and an optimum region for setting the liquid charging position for this powdery or granular raw material charging position on the bottom of the pan of the pan-type pelletizer. FIG. 4 is an explanatory diagram showing another example of the powdery or granular raw material charging position in the method of the present invention, and an optimum region for setting the liquid charging position for this powdery or granular raw material charging position on the bottom of the pan of the pan-type pelletizer. FIG. 4 is an explanatory view showing the powdery or granular raw material charging position and the liquid charging position in the embodiment on the pan bottom surface of the pan-type pelletizer.

In the granulation of powdery or granular raw materials by a pan-type pelletizer, the present inventors have determined the input position of the powdery or granular raw materials and the liquid that contributes to the adhesion between the powdery or granular materials (liquid for obtaining liquid bridging force). It is simply referred to as "liquid"). FIG. 1 schematically shows an example of a pan-type pelletizer to which the method of the present invention can be applied. 1 is a side view of bread 1; FIG. In the following description, the bottom surface of the pan 1 refers to a circular plate surface (upper surface) on which the granular raw material rolls and is granulated. The pan 1 consists of a circular bottom plate portion 10 and a side wall portion 11 surrounding the bottom plate portion 10. The pan 1 is normally held in a state (inclined state) at a certain angle θ from the horizontal, and rotated in this inclined state. do. In the example of FIG. 1, pan 1 rotates counterclockwise as shown by the arrow. Note that the pan 1 shown in FIGS. 2 to 12, which will be described later, also rotates counterclockwise.

The scraper 2 is a plate-like member that scrapes off the powdery or granular material adhering to the side wall surface or the bottom surface of the pan 1 and guides downward the powdery or granular material that has moved upward from the inclined bottom surface of the pan 1 . , has the function of regulating (restricting) the rolling area of the powdered or granular raw material on the bottom surface of the pan. In the absence of the scraper 2, the powder or granular raw material rotates while adhering to the side wall surface of the pan 1 or the like. The scraper 2 is supported by a support arm (not shown), and one end 20 of the scraper 2 is adjacent to the side wall surface at the inclined top A of the bottom surface of the pan 1 or its peripheral portion (the top A of the pan 1 in the example of FIG. 1). and the longitudinal direction thereof is the side where the upper half of the pan rotates (the upper half of the pan indicated by the arrow in FIG. rotation direction). The scraper 2 in FIG. 1 has a length substantially equal to the radius of the pan 1, and is arranged in a state inclined by about Φ30° from a perpendicular line g on the bottom of the pan passing through one end 20 thereof.

FIGS. 2 and 3 schematically show other examples of pan-type pelletizers to which the method of the present invention can be applied, and are plan views showing the arrangement of a pan 1 and a scraper 2 relative thereto. In the pan-type pelletizer of FIG. 2, the scraper 2 has a length of about 1/3 of the diameter of the pan 1, and one end 20 of the scraper 2 is close to the side wall surface at the periphery of the top A of the inclined bottom surface of the pan 1. 40° from the vertical line g on the bottom of the pan passing through the one end 20 . In the pan-type pelletizer shown in FIG. 2, one end 20 of the scraper 2 is located on the sidewall surface side, and extends horizontally around the position of the top A to about 1/4 of the radius of the pan 1 (specifically, radius x 0.24), and in the periphery, which is approximately 1/10 of the radius of pan 1 in the vertical direction (specifically, radius x 0.06).

On the other hand, the pan-type pelletizer of FIG. 3 has a plurality of scraper members 2a (two scraper members 2a in the example of FIG. 3) arranged parallel to each other and spaced apart in the vertical direction of the inclined pan 1. ). Each scraper member 2a is a short member having a length of about 1/4 to 1/3 of the radius of the pan 1, and the uppermost scraper member 2a has an inclined bottom surface of the pan 1 at one end 20a. is positioned close to the side wall surface (side wall surface side) in the periphery of the top A of the pan, and the longitudinal direction thereof is the side on which the upper half of the pan rotates with respect to the radial direction of the pan with one end 20a as the base point (Rotational direction of the upper half of the pan indicated by the arrow in FIG. 3). The uppermost scraper member 2a in FIG. 3 is arranged in a state inclined by about Φ15° from the vertical line g on the bottom of the pan passing through its one end 20a, and the other scraper members 2a below it are also arranged at the same inclination. It is The scraper 2 may be composed of three or more scraper members 2a. In the pan-type pelletizer shown in FIG. 3, one end 20a of the uppermost scraper member 2a is located on the side of the side wall and extends horizontally around the position of the top A to about 1/2 of the radius of the pan 1 (details ), and in the vertical direction, in the peripheral area of about 1/10 the radius of Pan 1 (specifically, the radius x 0.11). .

Although the pan-type pelletizer may be operated in batch mode, it is generally industrially operated continuously. inserted continuously. Binders for facilitating granulation are added to powdery or granular raw materials in anticipation of thickening and hardening effects, and various inorganic or organic solid or liquid binders are used depending on the application. However, for example, when granulating a sintering raw material for producing sintered ore (a mixed raw material of fine ore and auxiliary raw materials), generally about 1 to 2% by mass of quicklime is blended with the sintering raw material. . In addition, the liquid is introduced in an amount in which the liquid bridging force works effectively with respect to the powder raw material, but when granulating the sintering raw material for producing sintered ore, it is generally 8 to 12 masses. %, the adhesion is high, and the adhesion is lowered outside this range, so it is common to add water within this range.

The present inventors investigated the raw material behavior in the pan during the granulation process of the granular raw material by the pan-type pelletizer. It was found that the movement shown in . That is, FIG. 4 is an explanatory diagram schematically showing the movement of the powdery or granular raw material in the pan 1 during the granulation process, and FIG. 4(a) shows the movement of the intermediate layer 31 of the granular material layer 3, and FIG. 4(c) shows the movement of the surface layer 32 of the granular material layer 3, respectively. Note that p ₃₀ , p ₃₁ , and p ₃₂ in the figure indicate the rotating vortex center of each layer.

According to FIG. 4, the rotating vortex of the granular raw material becomes smaller from the bottom layer 30 to the surface layer 32, and the center of the rotating vortex shifts from the right side of the pan center toward the lower right as viewed in the figure. Ungranulated raw material particles tend to be distributed on the bottom layer 30, and granulated materials tend to be distributed on the surface layer 32. The granulated materials are discharged out of the pan from the bottom right and collected as a product. Since the granules are likely to be distributed in the lower right part of the drawing, the charging position of the powdery or granular raw material (pan bottom area where the charged powdery or granular raw material falls; 1, inside the scraper 2 (exactly, the side surface of the scraper 2 that serves as the raw material scraping surface) and the imaginary straight line on its extension (center side of the bottom of the pan), and the feeding position of the powdery or granular raw material It can be seen that it is desirable for the center to be on the scraper 2 side of the imaginary straight line passing through the center of the bottom surface of the pan and parallel to the scraper.

In addition, when the powdery grain material rolls down from the top of the pan 1, the powdery grains come into contact with each other, and the liquid that exerts the liquid bridging force intervenes to promote adhesion between the powdery grains. In order to efficiently and evenly disperse the liquid, the liquid charging position (pan bottom area where the charged liquid drops; the same shall apply hereinafter) should be the side where the powdery or granular raw material rolls down from above, and the powdery or granular raw material is granulated. It can be seen that the region in which the transition is not progressed is good. That is, it is appropriate to put in the left side of the pan 1, which is the position where the powdery or granular material shown in FIG. It is desirable to be on an imaginary straight line parallel to the scraper 2 passing through the center of the throwing position. However, since there is no big problem even if the center of the liquid input position deviates slightly from the imaginary line, the center of the liquid input position is the scraper 2 passing through the input position of the powdery or granular raw material (it does not have to be the input position center). It suffices if it is on a parallel imaginary straight line.

Furthermore, the powdery or grainy raw material stays near the point where the raw material collides with the scraper 2 and starts to fall, and also stays near the start of lifting along the side wall of the pan 1 after dropping. For this reason, the vicinity of the outer edge of the pan 1 is not desirable as a liquid introduction position. Therefore, it is preferable that the liquid input position is positioned so that the center of the liquid falls within a circle having a radius of about 0.6r with respect to the radius r of the pan 1 .

Therefore, in the present invention, the raw material powder and the liquid are put into the pan 1 under the following conditions. FIG. 5 shows, in the method of the present invention, a powdery or granular raw material charging position x on the bottom surface of the pan 1 (a pan bottom area where the charged powdery or granular raw material falls; the same shall apply hereinafter) and a liquid charging position y (where the charged liquid drops). FIG. 10 is an explanatory diagram showing a falling bread bottom area (the same applies hereinafter). First, regarding the charging of the powdered or granular raw material, a straight line intersecting a virtual extended surface of the side surface 21 of the scraper 2 (a side surface that serves as a raw material scraping surface) on the bottom surface of the pan 1 and When a straight line passing through the center p of the bottom surface and parallel to the virtual straight line a is defined as a virtual straight line b, the powdery or granular raw material input position x is closer to the center p side of the bottom of the pan 1 than the virtual straight line a, and the powdery or granular material The raw material powder is charged into the pan 1 so that the center px of the raw material charging position _x is located between the imaginary straight line a and the imaginary straight line b.

In addition, regarding liquid input, on the bottom surface of the pan 1, the center py of the liquid input position _y passes through the granular raw material charging position x (it may pass through any part of the granular raw material charging position x). , and positioned on a virtual straight line c parallel to the virtual straight line a. Here, the fact that the center py of the liquid input position _y is located on the imaginary straight line c that passes through the powder material input position x and is parallel to the imaginary straight line a means that the powder in the horizontal direction as shown in FIG. If straight lines passing through both ends f ₁ and f ₂ of the granular raw material charging position x and parallel to the virtual straight line a are assumed to be virtual straight lines c1 and c2, the center p _y of the liquid charging position y is the virtual straight line c1 and the virtual straight line. c2.

FIG. 6 is an explanatory diagram showing the powdery or granular raw material input position x and the liquid input position y on the bottom surface of the pan 1 when the pan-type pelletizer of the type shown in FIG. 3 is used in the method of the present invention. On the inclined bottom surface of the pan 1, a straight line intersecting virtual extended surfaces of the side surface 21a (the side surface serving as the raw material scraping surface) of the uppermost scraper member 2a and its extension line are assumed to be a virtual straight line a. Other conditions are the same as those in FIG. 5, so the same reference numerals are given and detailed description thereof is omitted.

Further, in the method of the present invention as described above, as a particularly preferable condition, it is preferable that the center py of the liquid input position _y is positioned below the granular raw material input position x on the inclined bottom surface of the pan 1 . 7 and 8 schematically show the states of the powdery or granular material and the liquid when the liquid input position y is below and above the powdery or granular material input position x on the bottom surface of the inclined pan 1. typically shown. In addition, in the figure, the raw material regions of the bottom layer 30, intermediate layer 31, and surface layer 32 of the granular material layer 3 in the pan 1 are also shown. FIG. 7 shows the case where the liquid input position y is below the granular raw material input position x, FIG. 7(a) shows the side surface of the pan 1, and FIG. It is explanatory drawing which shows each. FIG. 8 shows the case where the liquid input position y is above the granular raw material input position x, and FIG. 8(a) shows the side of the pan, and FIG. 8(b) shows the bottom of the pan. It is a diagram.

When the liquid input position y is below the granular material input position x as shown in FIG. 7, when the newly input granular material rolls down, it passes through the liquid input area (liquid input position y). By doing so, it comes into contact with the liquid efficiently. On the other hand, when the liquid input position y is above the powder material material input position x as shown in FIG. 8, the liquid permeates the powder material layer. Also, since the liquid is mainly sprayed on the powdery or grainy raw material already in the pan 1, it is difficult for the introduced liquid to come into uniform contact with the powdery or grainy raw material. That is, when the liquid input position y is lower than the granular raw material input position x, the liquid is more uniformly dispersed, and granules having uniform strength and size are more likely to be obtained.

FIG. 9 is an explanatory view showing an example of the powdery or granular raw material charging position x in the method of the present invention and a region where the liquid feeding position y is provided for the powdery or granular raw material charging position x on the bottom of the pan. In the method of the present invention, the powdery or granular raw material input position x is located on the center p side of the bottom surface of the pan 1 from the imaginary straight line a, and the center p _x is located between the imaginary straight lines a and b. However, in the example of FIG. 9, the powdery or granular raw material input position x itself falls between the imaginary straight line a and the virtual straight line b, and the center px of the powdery or granular raw material feeding position _x is located from the center p of the pan 1. , and is set to be positioned within the region e (the region within the circle having a radius of 0.6r with respect to the radius r of pan 1). The center py of the liquid input position _y is positioned on a virtual straight line c that passes through the granular raw material input position x and is parallel to the virtual straight line a (i.e., positioned between the virtual straight lines c1 and c2). ), and is set so as to fall within region e, so in the example of FIG.

FIGS. 10 and 11 respectively show another example of the powdery or granular raw material input position x in the method of the present invention and the optimum region for setting the liquid feeding position y with respect to the powdery or granular raw material feeding position x on the bottom of the pan. FIG. 2 is an explanatory diagram showing a case where the liquid input position y is set below the granular raw material input position x. In the example of FIG. 10, the powder or granular raw material input position x is set above the region e (the region within the circle having a radius of 0.6r with respect to the radius r of the pan 1), so the liquid input position y will be set to the grid area. On the other hand, in the example of FIG. 11, since the powdery or granular raw material input position x is set within the region e, the liquid input position y is set in a narrow grid pattern region.

In the present invention, any method may be used to charge the raw material into the charging position x, and there is no particular limitation. can be put in. Moreover, the method of injecting the liquid into the injecting position y is also arbitrary, and the liquid may be injected (sprinkled) with a hose, or injected (sprayed) with a sprinkling means such as a water sprinkling nozzle.

There is no particular limitation on the granulation object of the method of the present invention, and various powdery or granular raw materials can be granulated. Suitable for In the granulation of sintering raw materials for producing sintered ore, in order to produce high-quality sintered ore, granules (pseudo-particles) that have predetermined strength and particle size and have small variations in strength and particle size However, according to the granulation method of the present invention, such granules can be stably obtained. Granules of sintering raw materials for producing sintered ore granulated by the method of the present invention are charged into a sintering machine (usually a Dwight Lloyd sintering machine) and sintered, and are used as an iron source for a blast furnace. sintered ore is produced.

A granulation test of sintering raw materials for producing sintered ore was conducted using a pan-type pelletizer. The raw material for sintering is raw material fine powder (arithmetic mean diameter: 1 mm) composed of iron ore, limestone, and quicklime. The pan of the pan-type pelletizer had a diameter of 1.2 m, a side wall height of 0.2 m, an inclination angle θ of 51°, and was operated at a rotational speed of 18 rpm. This granulation test was carried out under conditions 1 and 2 (comparative examples) and conditions 3 and 4 (invention examples) in which the liquid input position y was changed with respect to the predetermined powder material raw material input position x. did.

FIG. 12 shows the powdery or granular raw material input position x and the liquid feeding position y on the bottom of the pan. , X = -0.205, Y = -0.075, and the width was 265 mm with the center p _x , and the sintering raw material was continuously charged to the charging position x at 15 kg/min. Moisture (liquid for obtaining liquid bridging force) was continuously injected at 1.3 L/min so that the center py of the liquid injection position _y was at the position (XY coordinates) shown in Table 1.

Condition 1 is that the center p _y of the liquid input position y is located on the imaginary straight line c that passes through the granular raw material input position x and is parallel to the imaginary straight line a (i.e., between the imaginary straight lines c1 and c2 ), but outside region e in a circle with radius 0.6r. On the other hand, in condition 2, although the center p _y of the liquid input position y is in the area e in the circle with a radius of 0.6r, the virtual This is a comparative example not located on the straight line c (that is, not between the virtual straight lines c1 and c2). Condition 3 is an invention example in which the center py of the liquid charging position _y is above the granular raw material charging position x. On the other hand, Condition 4 is an invention example in which the center py of the liquid charging position _y is below the granular raw material charging position x.

After 6 minutes, 7 minutes, and 8 minutes after the start of the operation of the pan-type pelletizer, 3 kg samples of the granulated material discharged outside the pan were collected three times, and a total of 9 kg was obtained for each condition. The particle size distribution of the sample was investigated. Manual sieving is performed with sieve openings of 2 mm, 4.75 mm, 8 mm, 11.2 mm, and 13.2 mm. 3.37 mm, and the standard particle size of other samples on and under the sieve was similarly obtained (however, the sample under the 2 mm sieve had a standard particle size of 1 mm, and there was no sample on the 13.2 mm sieve). , weighted by their mass proportions to calculate the average particle size. The standard deviation was determined as the positive square root of the value obtained by dividing the sum of the squares of the differences between each reference particle size and the average particle size weighted by the mass ratio by the total mass ratio of 100%. Table 2 shows the average particle size and standard deviation. From these results, it can be seen that the variation in particle size is smaller under conditions 3 and 4, which are examples of the invention, than

conditions

1 and 2, which are comparative examples.

In addition, 10 granules with a particle size in the range of 4.75 to 8.00 mm were extracted for each condition, and a uniaxial compression test was performed on them to examine the crushing strength. The uniaxial compression test was performed using a testing machine specified in JIS A1216, and the maximum compressive stress was taken as the crushing strength. Table 3 shows the arithmetic mean of the crushing strength and its standard deviation (the positive square root of the value obtained by dividing the sum of the squares of the difference between the value of each data and the mean by the total number of data n). From these results, it can be seen that the variations in crushing strength are smaller under conditions 3 and 4, which are invention examples, than under

conditions

1 and 2, which are comparative examples.

Reference Signs List 1 Pan 2 Scraper 2a Scraper member 3 Granular raw material layer 10 Bottom plate portion of pan 11 Side wall portion of pan 20 One end portion of scraper 20a One end portion of scraper member 21 Side surface of scraper (side surface serving as a raw material scraping surface)
21a side surface of scraper member (side surface serving as raw material scraping surface)
30 Bottom layer 31 Intermediate layer 32 Surface layer A Top of pan x Position of powdery or granular raw material input y Position of liquid input a, b, c, c1, c2 Imaginary straight line e Areas within a circle with a radius of 0.6r f ₁ , f ₂ Edge of powdery or granular material input position x g Vertical line p Center of pan bottom p _x Center of powdery or granular material input position x p _Y Center of liquid input position y p ₃₀ , p ₃₁ , p ₃₂ Rotating vortex center of raw material

Claims

A pan (1) rotating in an inclined state, scraping off the powdery or granular raw material adhering to the side wall surface and the bottom surface of the pan (1), and a rolling area of the powdery or granular raw material on the bottom surface of the pan (1) One end (20) of the scraper (2) is located on the side wall of the inclined pan (1), and the longitudinal direction of the scraper (2) is one end (20 ) is used as a base point, and a pan-type pelletizer is arranged in a state in which the upper half of the pan is inclined toward the rotating side with respect to the radial direction of the pan. A method of granulating a powdery or grain raw material by introducing a liquid of
On the bottom surface of the pan (1), a straight line intersecting the imaginary extended surface of the side surface (21) of the scraper (2) (the side surface that serves as the raw material scraping surface) and its extension line are imaginary straight lines (a), pan (1) When a straight line passing through the center (p) of the bottom surface and parallel to the virtual straight line (a) is defined as a virtual straight line (b), the powdery or granular raw material input position (x) (provided that the powdery or granular raw material is The area of the bottom of the pan where it falls) is closer to the center (p) of the bottom of the pan (1) than the imaginary straight line (a), and the center (p x ) of the feeding position (x) of the powdery or granular raw material is aligned with the imaginary straight line (a). and put the raw material into the pan (1) so that it is positioned between the virtual straight line (b),
On the bottom surface of the pan (1), the center (p y ) of the liquid input position (y) (however, the pan bottom area where the input liquid drops) passes through the granular raw material input position (x), and the virtual Pan the liquid so that it lies on an imaginary straight line (c) parallel to the straight line (a) and enters a region (e) within a circle having a radius of 0.6r with respect to the radius r of the pan (1). (1).
The powder according to claim 1, characterized in that the center (p y ) of the liquid input position (y) is positioned below the powdery or granular raw material input position (x) on the inclined bottom surface of the pan (1). A method for granulating a granular raw material.
The scraper (2) consists of a plurality of scraper members (2a) spaced apart in the vertical direction of the inclined pan (1), of which the uppermost scraper member (2a) has one end (20a) ) is located on the side wall side of the inclined pan (1), and its longitudinal direction is inclined to the side where the upper half of the pan rotates with respect to the radial direction of the pan with one end (20a) as the base point. is placed in
On the bottom surface of the pan (1), the imaginary straight line (a) is the intersection of the imaginary extension planes of the side surfaces (21a) of the uppermost scraper member (2a) (the side surfaces that serve as the raw material scraping surfaces) and their extension lines. 3. The method for granulating a powdery or granular raw material according to claim 1 or 2, characterized in that:
The method for granulating a powdery or granular raw material according to any one of claims 1 to 3, wherein a sintering raw material for producing sintered ore is granulated as the powdery raw material.
A method for producing sintered ore, comprising granulating a sintering raw material for producing sintered ore by the granulating method according to claim 4 and sintering the granules.